Cytochemical and molecular biological study of enamel proteins with special reference to dental hard tissue formation

本研究应用生物化学、免疫化学、免疫细胞化学和分子生物学方法，对猪和大鼠的牙釉质发生进行了研究。结果总结如下。(1)釉原蛋白、釉蛋白和鞘蛋白在猪牙胚分化至过渡期表达，而在大鼠切牙和磨牙牙胚中表达直至早期成熟。这些结果提示，釉蛋白在猪和大鼠釉质发育过程中的作用可能不同。(2)在牙根形态发生和形成过程中，大鼠鞘蛋白（成釉蛋白和釉蛋白）在部分牙周细胞和牙骨质细胞中表达，这两种细胞都具有上皮起源的特征，如张力丝束和桥粒，这表明起源于Hertwig上皮根鞘的细胞实际上合成并分泌鞘蛋白。另一方面，在猪组织中， ...更多信息 除成釉细胞外，牙胚细胞成分中均未发现有基因组蛋白和鞘蛋白。这些结果表明，存在鞘蛋白的物种差异有关的细胞中的表达Hertwig的上皮根鞘和诱导成牙骨质细胞的作用之间的猪和大鼠。(3)釉质溶素是釉质特异性基质金属蛋白酶之一，在猪和大鼠未成熟釉质中以46 kDa和44 kDa蛋白的活化形式被免疫定位。在猪牙胚中，在分泌期，免疫反应除未成熟釉质表层外较弱，而从过渡到早期成熟阶段，免疫反应在釉质基质表层较强。EMSP1（釉丝氨酸基质蛋白酶1）的免疫反应也强烈的过渡到早期成熟阶段的釉基质的表层。这些结果表明，过渡性成釉细胞在成熟成釉细胞吸收前的基质降解中起重要作用。少

Amelogenesis of the porcine and the rat was investigated by means of biochemical, immunochemical, immunocytochemical and molecular biological methods. The results are summarized as follows.(1) Amelogenins, enamelins and sheath proteins were expressed in porcine tooth germs from the differentiation to the transition stage, while they were expressed in rat incisor and molar tooth germs until early maturation stage. These results suggest that the role of enamel proteins in enamel maturation might be different between the pig and the rat amelogenesis.(2) During root morphogenesis and formation, rat sheath proteins (ameloblastin and amelin) were expressed in a part of periodontal cells and cementocytes, both of which have characteristic features of epithelial origin such as tonofilament bundles and desmosomes, suggesting that cells originated from Hertwig's epithelial root sheath actually synthesize and secret sheath proteins. On the other hand in porcine tissues, expression of neither amel … More ogenins nor sheath proteins was found any cellular elements of tooth germs except for ameloblast. These results suggest that presence of species difference of sheath proteins concerning the expression in cells related to Hertwig's epithelial root sheath and the role of induction of cementoblasts between the pig and that rat.(3) Enamelysin, one of enamel specific matrix metalloproteinases, was immunolocalized in the immature enamel of the pig and the rat as an activated form of 46 kDa and 44 kDa protein. In porcine tooth germs, immunoreaction was weak except for the surface layer of immature enamel at the secretory stage, while it was intense over the superficial layer of enamel matrix from the transition to the early maturation stage. Immunoreaction of EMSP1 (enamel serine matrix proteinase 1) was also intense over the superficial layer of enamel matrix from the transition to the early maturation stage. These results suggest that transitional ameloblasts play a important role on matrix degradation prior to resorption by maturation ameloblasts. Less